A sample of gas in a balloon has an initial temperature of 43∘C and a volume of 1.69×103L . If the temperature changes to 76∘C , and there is no change of pressure or amount of gas, what is the new volume, V2, of the gas?
At constant pressure the volume will be proportional to the absolute temperature.
V2/(273+76) = 1690/(273+43) (i've assumed your 1.69x103L means 1.69x103L)
Can you take it from here?